Refer to Example 5.3. Suppose we continue to estimate σ with .a. If the level of confidenc...

Refer to Example 5.3. Suppose we continue to estimate σ with .

a. If the level of confidence remains at 95% but the tolerable width is 1, how large a sample size is required?

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b. If the level of confidence increases to 99% but the specified width remains at 1.2, how large a sample size is required?

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c. If the level of confidence decreases to 90% but the specified width remains at 1.2, how large a sample size is required?

Example 5.3

Refer to Exercise 5.2. How might you select a sample of fuses from the manufacturer to test the claim?

Exercise 5.2

A manufacturer claims that the average lifetime of a particular fuse is 1, 500 hours information from a sample of 35 fuses shows that the average lifetime is 1, 380 hours. What can be said about the manufacturer’s claim?

a. Identify the population of interest to us.

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b. Would an answer to the question posed involve estimation or testing a hypothesis?